Method and recorder for recording data on a record carrier

ABSTRACT

When a write error occurs on a write once recording medium the recording medium is currently discarded. By retrieving the location of the last recorded data block from the recorded area indicator on the recording medium a starting point for the search for the next empty data block suitable for recording is obtained. By searching for an empty data block the data blocks comprising write errors following the last recorded data block are skipped and the recording is continued at the empty data block found. After finishing the recording and writing the lead-in and lead-out information a record carrier is obtained that can be played in standard players.

The invention relates to a method for recording data on a write oncerecord carrier with sequential write access and a recorded areaindicator and a last recorded data block with a location,

comprising the steps of

recording information in a data block

updating the recorded area indicator to reflect the recording ofinformation in the data block

and to a recorder for recording information on a write once recordcarrier with sequential write access and a recorded area indicator and alast recorded data block with a location, the recorder comprising acontroller means, writing means, data retrieval means, and location oflast recorded data block where the control means is operative to recordinformation in a data block sequentially following the last recordeddata block.

Such a method is known from state of the art recorders for opticalrecording media. An example of such a recorder is a DVD or Blue Diskrecorder capable of recording on a DVD+R or DVD-R or Blue Disk recordingmedium They comply with the DVD+R or Blue Disk standard. Those standardsprescribes that when a recording is resumed on a write once medium thedata block following the last recorded data block must be the first datablock to be recorded. On the recording medium defects can be present inECC blocks that lead to errors in the data recorded in those ECC blocks.The recorder aborts the recording when an error is detected in an ECCblock.

When recording video data in DVD+VR format all of the video data isplaced in a single track. A write error resulting in a defect ECC blockresults in an unusable recording medium.

The draw back of such a method is that the recorder must discard thewrite once record carrier.

It is an objective of the present invention to provide a method forrecording on a recording medium that allows the recording to be resumedregardless of the presence of data blocks comprising a write error.

To achieve this objective the method is characterized in that the methodfurther comprises the following steps if a data block with write erroris detected:

determining the location of the last recorded data block usinginformation from the recorded area indicator;

searching for an empty data block sequentially following the lastrecorded data block

recording information in the empty data block sequentially following thelast recorded data block.

Instead of discarding the recording medium the recording can be resumedby searching a section of the record carrier comprising a limited numberof data blocks as indicated by the recorded area indicator as comprisingthe last recorded data block, skipping the data block or data blocksthat sequentially follow last recorded data block by searching for anempty data block and resuming the recording starting with the empty datablock found. A playback device that will later playback the recordcarrier is not affected by the skipped data blocks since it will ignorethese data blocks and will continue the playback with the firstsequentially found data block that is not defective.

The record carrier no longer has to be discarded during the recordingoperation because of a write error, thus achieving the objective of theinvention.

The recorded area indicator provides an indication which section of therecording medium is already recorded and which section remains empty.Because the recording medium is recorded in a sequential fashion, thelast recorded data block can be found at the boundary between thesection already recorded and the section that is still empty.

The presence of skipped data blocks in the section already recorded isconsequently of no influence to the searching of the last recorded datablock when using this method, rendering a recording medium with skippeddata blocks suitable for resuming recordings.

An embodiment of the method is characterized in that the informationfrom the recorded area indicator comprises an indication of a set ofcontiguous data blocks comprising the last recorded data block.

The recorded area indicator represents the data blocks already recordedwith an entry in the recorded area indicator. Each entry represents apredetermined number of data blocks. Consequently an entry can representa single data block or it can represent multiple data blocks. When theentry represents a single data block, applying the method only involvesdetermining the last entry in the recorded area indicator, andtranslating this entry into the exact location of the last recorded datablock. When the entry represents multiple recorded data blocks, applyingthe method involves determining the set of data blocks comprising thelast recorded data block and subsequently searching this limited numberof data blocks on the recording medium to find the last recorded datablock. Subsequently after the last recorded data block has been foundthe data blocks comprising a write error are skipped by searching for anempty data block. A data block comprising a write error is not empty sosearching for an empty data block automatically means that data blockscomprising a write error are skipped because they do not qualify asempty.

A further embodiment of the method is characterized in that based on theindication of a set of contiguous data blocks comprising the lastrecorded data block the set of contiguous data blocks is searched forthe location of the last recorded data block.

When the entry represents multiple recorded data blocks, applying themethod involves determining the set of data blocks comprising the lastrecorded data block and subsequently searching this limited number ofdata blocks on the recording medium to find the last recorded datablock.

Because this search is limited to the set of data blocks indicated bythe recorded area indicator as comprising the last recorded data blockthe search can be performed in an acceptable amount of time.

Even if the set of data blocks indicated by the recorded area indicatoras comprising the last recorded data block comprises skipped datablocks, the search is not hampered because the last recorded data blockcan be found by searching from the end of the set of data blocks, thuscompletely ignoring the presence of skipped data blocks before the lastrecorded data block because the search does not involve the data blocksbefore the last recorded data block.

Alternatively the search can start from the beginning of the set of datablocks indicated by the recorded area indicator. When skipped datablocks are encountered the search can continue in order to ensure thatthe last recorded data block is found.

Since the search does not extend beyond the set of data blocks indicatedby the recorded area indicator the search effort is still limited andcan be performed in an acceptable amount of time.

In this way the recorder does no longer need to search the entire diskand is no longer affected by the presence of skipped data blocks, makingit feasible to resume recording on the recording medium in an acceptableamount of time.

Well known techniques for finding the first empty data blocksequentially following the last recorded data block can be applied.

A recorder according to the invention is characterized in that thecontroller means is coupled to the data retrieval means and is operativeto retrieve the recorded area indicator using the data retrieval meansand is further operative to search an empty data block sequentiallyfollowing the last recorded data block using the data retrieval meansand the recorded area indicator.

Instead of searching the entire recording medium to locate the lastrecorded data block the recorder can retrieve the recorded areaindicator from the recording medium. The recorded area indicatorprovides an indication which section of the recording medium is alreadyrecorded and which section remains empty. Because the recording mediumis recorded in a sequential fashion, the last recorded data block can befound at the boundary between the section already recorded and thesection that is still empty.

The presence of skipped data blocks in the section already recorded isconsequently of no influence to the searching of the last recorded datablock when using this method, rendering a recording medium with skippeddata blocks suitable for resuming recordings.

By subsequently searching for an empty data block sequentially followingthe last recorded data block any data block comprising a write error areskipped and the recording can be resumed starting at the empty datablock.

Thus the loss of the write once recording medium is avoided.

An embodiment of the recorder is characterized in that the recorded areaindicator comprises an indication of a set of contiguous data blockscomprising the last recorded data block.

The recorded area indicator represents the data blocks already recordedwith an entry in the recorded area indicator. Each entry represents apredetermined number of data blocks. Consequently an entry can representa single data block or it can represent multiple data blocks. When theentry represents a single data block, applying the method only involvesdetermining the last entry in the recorded area indicator, andtranslating this entry into the exact location of the last recorded datablock. When the entry represents multiple recorded data blocks, applyingthe method involves determining the set of data blocks comprising thelast recorded data block and subsequently searching this limited numberof data blocks on the recording medium to find the last recorded datablock.

A further embodiment of the recorder is characterized in that based onthe indication of a set of contiguous data blocks comprising the lastrecorded data block the set of contiguous data blocks is searched forthe location of the last recorded data block.

When the entry represents multiple recorded data blocks, applying themethod involves determining the set of data blocks comprising the lastrecorded data block and subsequently searching this limited number ofdata blocks on the recording medium to find the last recorded datablock.

Because this search is limited to the set of data blocks indicated bythe recorded area indicator as comprising the last recorded data blockthe search can be performed in an acceptable amount of time.

Even if the set of data blocks indicated by the recorded area indicatoras comprising the last recorded data block comprises skipped datablocks, the search is not hampered because the last recorded data blockcan be found by searching from the end of the set of data blocks, thuscompletely ignoring the presence of skipped data blocks before the lastrecorded data block because the search does not involve the data blocksbefore the last recorded data block.

Alternatively the search can start from the beginning of the set of datablocks indicated by the recorded area indicator. When skipped datablocks are encountered the search can continue in order to ensure thatthe last recorded data block is found.

Since the search does not extend beyond the set of data blocks indicatedby the recorded area indicator the search effort is still limited andcan be performed in an acceptable amount of time.

In this way the recorder does no longer need to search the entire diskand is no longer affected by the presence of skipped data blocks, makingit feasible to resume recording on the recording medium in an acceptableamount of time.

The invention will now be discussed based on figures.

FIG. 1 shows a disc with a write error as resulting from applying theprior art.

FIG. 2 shows a disc with a write error as recorded using the presentinvention.

FIG. 3 shows a flow diagram of the method of the invention.

FIG. 4 shows a recorder.

FIG. 1 shows a disc with a write error as resulting from applying theprior art.

A track 1 on a record carrier comprises a lead-in section 2 reserved forwriting lead-in information, a recorded area 3, a data block comprisingdata block 4 comprising a write error and an empty section 5 comprisingempty data blocks.

When the recorder starts recording the data on the record carrier itsuccessively writes sequentially arranged data blocks. This results in arecorded area 3. The lead-in information and lead-out information is atthis point not yet recorded since that is done when the entire track 1has been recorded.

When the recorder encounters a data block 4 comprising a write error,which may be caused by surface damage or contamination or a loss oftracking during the write operation, the recorder aborts the recordingoperation. Consequently the empty section comprising empty data blockswill not be recorded. The lead-in and lead-out information are notrecorded on the record carrier resulting in an un-useable recordcarrier.

FIG. 2 shows a disc with a write error as recorded using the presentinvention

A track 21 on a record carrier comprises a lead-in section 22 reservedfor writing lead-in information, a recorded area 23, a data blockcomprising data block 24 comprising a write error and an empty section25,26,27 comprising empty data blocks.

When the recorder starts recording the data on the record carrier itsuccessively writes sequentially arranged data blocks. This results in arecorded area 23. The lead-in information and lead-out information is atthis point not yet recorded since that is done when the entire track 21has been recorded.

When the recorder encounters a data block 24 comprising a write error,which may be caused by surface damage or contamination or a loss oftracking during the write operation, the recorder aborts the recordingoperation. Subsequently the recorder retrieves the recorded areaindicator from the record carrier. Based on the recorded area indicatorthe recorder searches for the last recorded data block which is the lastcorrectly recorded data block of the recorded are 23. Once this lastrecorded data block is found the recorder searches for an empty datablock 25 sequentially following on the last recorded data block, i.e.subsequently following on the recorded area 23. The data block 24comprising the write error is not empty since some data has been writtenand is thus skipped by the recorder. The recorder resumes the recordingwith the first empty data block 25 found, completing the recording byrecording the remaining data section 26 of the track.

Finally the lead-in information is recorded in the lead-in section 22and the lead-out information is recorded in the lead-out section 27.

The result of this is a record carrier that can be played by playbackdevices since all relevant information is present on the record carrierand the data block 24 skipped during recording is also skipped by theplayback device because of the read error resulting from the writeerror. The record carrier is thus no longer discarded by the recorder.

FIG. 3 shows a flow diagram of the method of the invention

The first step comprises the recording of data in data blocks.

Subsequently, in the second step the recorder checks whether writeerrors occurred.

This can be done via data verification, i.e. read after write, or bydetecting loss of tracking. If no write error is detected the recorderreturns to the first step and the recording operation is continued ifrequired

When a write error is detected the recorder aborts the recordingoperation and proceeds to the third step where the recorded areaindicator is retrieved, either from memory or from the record carrier.Retrieving the recorded area indicator from the record carrier allowsthe record carrier to be removed from the recorder before resuming therecording operation, for instance to clean the surface of the recordcarrier. The recorded area indicator provides information about whichgroups of data blocks have been recorded and which data blocks are stillavailable for recording. Because the record carrier is sequentiallyrecorded the last entry in the recorded area indicator indicating arecorded group of data blocks corresponds to a group of data blocks onthe record carrier comprising the last recorded data block.

In the fourth step the recorder searches the group of data blocksindicated by the recorded area indicator as comprising the last recordeddata block for the last recorded data block.

Following this last recorded data block there may be data blockcomprising write errors and the recorder must ensure that no new attemptto record data in these data blocks is attempted. The recorder insteadsearches, in the fifth step, for the next available empty data blocksequentially following on the last recorded data block and thus alsofollowing the data blocks comprising a write error. In the sixth stepthe recorder resumes the recording in the first empty data blocksequentially following the last recorded data block as found inrespectively the fourth step and the fifth step.

It is clear that the recorder with the sixth step effectively returns tothe state of the first step when writing, i.e. further write errors leadto a repeat of the procedure outlined in FIG. 3.

Once all data has been recorded the record carrier is finalized byrecording the lead-in and lead-out information.

FIG. 4 shows a recorder

The recorder 30 for recording information on a record carrier comprisesa processor 31 coupled to an interface 32 for receiving a format commandor a close track session command through the interface 32 and is coupledto writing/reading means 33 in the form of a basic bit engine forwriting data.

The processor 31 receives information from the writing/reading means 33about write errors, for instance information about loss of trackingduring the recording operation.

The processor processes this information about write errors and providesthis information to a higher level application or another device coupledto the recorder via the interface 32. Alternatively the recorder 30 mayact on the write error information independently and provide noinformation about the write error via the interface 32.

The recorder further comprises a memory 35 coupled to the processor 31,and a user I/O device such as a keyboard/screen combination 36.

The method may be used by either the recorder 30 or the higher levelapplication or the method may be split up in tasks where the tasks aredivided over the recorder and the higher level application such as avideo recording application.

For instance the recording of the data can be controlled by the higherlevel application while the detection of the write errors must beperformed by the recorder. The determination of the last recorded datablock based on the recorded area indicator information can be performedby the higher level application while the search for an empty data blockcan be delegated to the recorder 30.

If the recorder 30 is powered down after the detection of a write errorbut before the resumption of the recording operation or the recordcarrier is ejected, the retrieval of the recorded area indication fromthe record carrier allows the recording operation to be resumed. If therecorded area indicator were not used the time needed to locate the lastrecorded data block would become excessive.

If the recorder 30 receives the eject disc command via the interface 32the recorder 30 operates the loading means (not shown) to eject therecord carrier comprising the updated recorded area indicator.

1. Method for recording data on a write once record carrier withsequential write access and a recorded area indicator and a lastrecorded data block with a location, comprising the steps of recordinginformation in a data block updating the recorded area indicator toreflect the recording of information in the data block characterized inthat the method further comprises the following steps if a data blockwith write error is detected: determining the location of the lastrecorded data block using information from the recorded area indicator;searching for an empty data block sequentially following the lastrecorded data block recording information in the empty data blocksequentially following the last recorded data block.
 2. Method asclaimed in claim 1, characterized in that the information from therecorded area indicator comprises an indication of a set of contiguousdata blocks comprising the last recorded data block.
 3. Method asclaimed in claim 2, characterized in that based on the indication of aset of contiguous data blocks comprising the last recorded data blockthe set of contiguous data blocks is searched for the location of thelast recorded data block.
 4. Recorder for recording information on awrite once record carrier with sequential write access and a recordedarea indicator and a last recorded data block with a location, therecorder comprising a controller means, writing means, data retrievalmeans, and location of last recorded data block where the control meansis operative to record information in a data block sequentiallyfollowing the last recorded data block, characterized in that thecontroller means is coupled to the data retrieval means and is operativeto retrieve the recorded area indicator using the data retrieval meansand is further operative to search an empty data block sequentiallyfollowing the last recorded data block using the data retrieval meansand the recorded area indicator.
 5. Recorder as claimed in claim 4,characterized in that the recorded area indicator comprises anindication of a set of contiguous data blocks comprising the lastrecorded data block.
 6. Recorder as claimed in claim 5, characterized inthat based on the indication of a set of contiguous data blockscomprising the last recorded data block the set of contiguous datablocks is searched for the location of the last recorded data block.